Bring the oil over medium heat in a medium sauce pan. Add the onions and cook for 3-5 minutes until translucent. Add the minced garlic and cook for an additional 30-60 seconds until garlic is fragrant. Add the chipotle peppers, tomato sauce, raspberries, brown sugar and cider vinegar and stir together. Bring to a boil and then reduce heat to simmer for about 15 minutes.

Using an immersion blender (or a regular blender), blend the sauce until smooth. Refrigerate in an airtight container until ready to use.

Set aside ½ cup of the Raspberry Chipotle BBQ sauce.

Pre-heat the grill to medium temperature. Place the pork tenderloins on the grill and grill until almost fully done (cooking times will vary by grill, ours took about 15-20 minutes). When the tenderloins are almost cooked, move them to indirect heat (either the top “bun shelf” if your grill has one or a burner that’s turned off with the other burners on high). Use a pastry brush to brush the top and sides of the tenderloins with about half of the reserved BBQ sauce. Close the lid and let it cook a few minutes while the sauce cooks on a bit. Flip the tenderloins and use the remaining sauce to brush the other side. Close the lid and finish cooking until pork is cooked through and juices run clear.